Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered elsewhere. The description adds the default 30-day window and the meaning of paid_only, which is useful context beyond the annotations, but it says nothing about the limit/cap behavior, result ordering, or what happens when no accounts match.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, front-loaded with the core definition and followed by the key modifier. Nothing is padded, though the parenthetical default and the second sentence could be merged into a tighter single statement.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

This is a simple read-only, zero-required-parameter tool, so the bar is low and the annotations plus schema carry much of the load. Still, with no output schema and 0% schema description coverage, the description should have covered the limit parameter and enough about the return shape (a list of accounts, and what fields/ordering) for an agent to use the results.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the full burden of explaining parameters. It clarifies days (inactivity threshold, default 30) and paid_only (restrict to paying customers), but leaves limit completely unexplained and gives no bounds for days even though the schema caps it at 365 with a minimum of 7.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a concrete resource and its defining filter: accounts with no activity within N days. That clearly separates it from generic siblings like list_users or get_active_users, though it is a noun phrase rather than an explicit verb and never states that it returns a list.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No when-to-use guidance is given and no alternatives are named. An agent choosing between this, find_users_without_event, and find_users_at_risk gets no help from the description; the only implied usage is the paid_only filter.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.